Steam-boiler.



r No. 694,493. Patented Mar. 4, |902. E. J. PENmNGToN,

STEAM- BUILEB. (Appximism 'and .rune 1o, 190m (Allo Modal.)

Wigesses p UNITED STATES PATENT OFFICE.

EDVARD J. PENNINGTON, LONDON, ENGLAND.

VSTEAM-Bonnin.

SPECIFICATION forming part of Letters Patent No. 694,493, dated March 4, 1 902.

v Application iiled June 10, 1901.

Be it known that I, EDWARD J. PENNING- TON, a citizen of the United States, residing at London, England, have invented new and useful Improvements in Steam-Boilers, of which the following is a specification.

My invention consists of an improvement in the construction of small boilers for generating steam, more especially for driving an automobile. In such boilers the combination of lightness with great strength and rapidsteaming qualities are especially desirable. I do not, however, limitthe use of my improvement to automobile-boilers, as it may be used in launches, for generating power to drive lathes, planers,and other machine-tools, and generally for purposes where the qualities before named are desired.

Myimproved boiler is of the nre-tube typethat is,I have an outer shellofsteel, iron, or other suitable metal, which shell is a cylindrical tube either cold-drawn or hot-drawn or it may be lap-welded. To' get the maximum of strength, I prefer the cold-drawn seamless steel tube, and in describing inyimprovement will confine myself to this material. l

I take a steel tube of the desired diameter and gage and cut it to the length required. I then take two disks of steel plating with which to make the heads of Vthe, boiler. On the periphery ofgeach disk .Itu'rn a screwthread which will engage and make a tight joint with an end of the cylinder internally threaded, and when these disks are screwed down a Water-tight boiler in the shape of a hollow drum will be formed.I To increase the heating-surface, however, before the insertion of the heads, I drill or punch in them a number of small holes at ,.intervals, and through the holes I pass metallic tubes -:eX- tending from one head'to the other. The ends of the tubes protrude from the outer face of each headsayfrom one-eighth to one-fourth ofan inch-and these ends are beaded or rolled over, so as to, make 4in each case a water-tight joint. Injthis waya firetube boiler is formed, a mainfeature of novelty being the screwing in' of theheads of the boilers. Insteady of using a head whichts the inside of the cylinder end, I may use a cap at each end, which screws upon the outer sain No. 64,036. (No modem wallof the cylinder, the necessary threadsenables me to readily separate for purpose of cleansing the outer shellof the boiler and the small tubes fixed in position in the two heads, whereby the whole may be exposed for inspection and removal of theimpurities and vscale which form obstructions and block the free circulation ofwater in boilers of this type where the space between the tubes does not often exceed one-fourth of an inch.

In the accompanying drawing, which shows the various steps in the formation of a boiler constituting my invention, Figure 1 represents the cylindrical shell of the boiler in its first orV original state. Figs. 2, 3, and 4 show the shell in different stages of formation. Fig. 5 indicates the heads of the cylinders with the series of tubes attached thereto. Fig. 6 shows the boiler assembled in its complete form.

Similar numerals of reference indicate similar parts in the respective gures.

I take a steel tube l-say eighteen inches long, with a fiveinch internal bore-and a three-sixteenths-of-an-inch gage, giving live and three-eighths inches outer diameter of tube-and use this as my boiler-shell. I then put'the tube in a lathe and take a cut of onesixteenth of an inch from the inner wall, commencing at one end and stopping, as shown by 2,d at three-eighths of an inch from the other end. In the three-eighths of an inch left ofthe original .thickness I cut a screwthread with a cutter inserted at the opposite end y'and running down the length of the tube.- Then at the other end of the tube, which noW has an enlarged internal diameter of veand one-eighth inches, I cut another thread (indicated by 4) `in the wall from the edge to three-eighths of an inch inward, the cutting-tool working in the same direction as when the first thread was cut. I thentake two steel plates 5 6-say three-eighths of an inch in thickness-cut into disks, the one, 5, being live inches in diameter and the other (marked 6) five and one-eighth inches, and ou the periphery of each disk I cut a thread IOO of the same pitch. Some forty holes (shown by 7) have rst been bored in each of these heads at suitable distances apart. A number of the disks or heads may be put into a gang-drill press and bored at one operation, insuring the holes being made parallel to those in the opposite head, or the holes may be punched or the heads may be of cast-steel with the holes lnade in the casting. Then I pass one-half-inch tubes 8 through the heads, leaving the outer walls of the heads eighteen inches apart, and secure the tubes 8 from slipping out of the holes inthe heads by beading, rolling, or spinning over the edges, as seen at 9, and forming a shoulder which will be a water-tight joint. When the whole of the tubes S are in position, I insert the head 5, which is five inches in diameter at the end of the cylinder, which is now five and oneeighth inches internal diameter, and push it down with the tubes 8 and the other head 6 attached to within three-eighths of an inch of the end of the cylinder, when the wall 2 with the screw-thread cut in it will be encountered. At this time the inner surface of the upper head 5 will be iiush with the top edge or rim of the cylinder l, and as both heads have suitable threads to engage with the respective threads cut in the cylinder by revolving the cylinder around the heads and tubes the several paris of the boiler will at one operation be screwed down into their places and perfect water-tight joints made in the shell without a single rivet being needed. The great advantage claimed for this construction is, however, the facility with which the internal parts of the boiler may be exposed, cleaned, and put together again. To readily accomplish the detachment, I may use a tool havingrods to pass through two or more tubes and adapted to be operated by a lever or handle at each end. lf the heads have not been unscrewed and the inner tubes withdrawn from the shell for a long period, the screws may have become so tight as to make it diiiicult to remove the heads. To overcome this objection, I may use a thin copper or other thimble or gasket between the outer and inner threads of each of the two screws, forming a good water and steam tight joint, which will not corrode and will permit the easy removal of the heads and inner tubes whenever desired.

The necessity of boring the interior of the shell, as already described, may be avoided by putting the shell in a lathe and spinning over one end, so as to reduce the diameter, into which reduced end may be cut the screwthread with which the smaller head is to engage. Instead of spinning over the end in a lathe the desired result may be attained by swaging or hydraulical pressing.

While I have described my invention in its preferred form, I do not limit myself to exact details of construction and combination, as minor changes may suggest themselves to the skilled mechanic without the exercise of invention, and such change not involving invention I consider as fully within the terms of my claims.

I claiml. A boiler consisting of a cylinder having at one end an internally-threaded part of diameter substantially equal to that of the major length of the cylinder, and at the opposite end an internally-threaded part of diameter less than that of said major portion, combined with heads and an assemblage of tubes connected to said heads, each head being externally threaded and engaging a threaded end of said cylinder, whereby the heads and assembled tubes may be inserted and withdrawn as an entirety, substantially as set forth.

2. A boiler consisting of a cylinder, heads and tubes, the heads supporting the tubes being secured to the cylinder by threads, substantially as set forth.

3. A boiler consisting of a cylinder, two heads, and an assemblage of tubes nested between and supported by said heads, the cylinder and heads being detachably united by screw-threads, substantially as set forth.

In testimony whereof I affix my signature in presence of two Witnesses.

EDWARD J. PENNINGTON.

Witnesses:

GEORGE II. HOWARD, JOHN B. ToBIN. 

